MRI and diffusion tensor imaging in assessing correlation of activation of cortical motor function and manifestations of corticospinal tract with muscle strength in patients with ischemic stroke

IN T R O D U C T IO N Ischem ic stroke is often follow ed by the abnorm alities ofneurons and corticospinaltract,w hich lead to corresponding clinicalsym ptom s and signs. R ecently, w ith the continuous perfection ofhigh-field M R Iin- strum ent, itis po…     

Cerebral cortical areas in which thickness correlates with severity of motor deficits of Parkinson’s disease

The pathology of Parkinson’s disease (PD) is not confined to the nigrostriatal dopaminergic pathway, but also involves widespread cerebral cortical areas. Such non-nigrostriatal lesions may contribute to disabling dopa-resistant parkinsonian motor deficits. We performed cortical thickness analysis to identify cerebral cortical brain areas in which thickness correlates with the severity of parkinsonian motor deficits. We performed T1-weighted brain magnetic resonance imaging studies in 142 PD patients. Motor scores on the Unified Parkinson’s Disease Rating Scale (UPDRS) were measured, and subscores were calculated for bradykinesia, rigidity, tremor, and axial motor deficits. Using FreeSurfer software, we studied cortical areas in which thickness correlates with disease duration or the severity of parkinsonian motor deficits. The cortical thickness of the parieto-temporal association cortex, including the inferior parietal and posterior parietal cortices, showed a negative correlation with disease duration, total UPDRS motor score, and UPDRS subscores for bradykinesia and axial motor deficits. We found no cortical areas in which thickness correlated with subscores for tremor and rigidity. In addition to nigrostriatal dopaminergic deficit, progressive thinning of the parieto-temporal sensory association cortices related to disease duration seems to be related in part to the exacerbation of bradykinesia and the axial motor symptoms of PD.     

Is the ipsilateral cortex surrounding the lesion or the non-injured contralateral cortex important for motor recovery in rats with photochemically induced cortical lesions?

PRIMARY OBJECTIVE: To determine whether the ipsilateral cortex surrounding the lesion or the non-injured contralateral cortex is important for motor recovery after brain damage in the photochemically initiated thrombosis (PIT) model. RESEARCH DESIGN: We induced PIT in the sensorimotor cortex in rats and examined the recovery of motor function using the beam-walking test. METHODS AND PROCEDURES: In 24 rats, the right sensorimotor cortex was lesioned after 2 days of training for the beam-walking test (group 1). After 10 days, PIT was induced in the left sensorimotor cortex. Eight additional rats (group 2) received 2 days training in beam walking, then underwent the beam-walking test to evaluate function. After 10 days of testing, the left sensorimotor cortex was lesioned and recovery was monitored by the beam-walking test for 8 days. MAIN OUTCOMES AND RESULTS: In group 1 animals, left hindlimb function caused by a right sensorimotor cortex lesion recovered within 10 days after the operation. Right hindlimb function caused by the left-side lesion recovered within 6 days. In group 2, right hindlimb function caused by induction of the left-side lesion after a total of 12 days of beam-walking training and testing recovered within 6 days as with the double PIT model. The training effect may be relevant to reorganization and neuromodulation. Motor recovery patterns did not indicate whether motor recovery was dependent on the ipsilateral cortex surrounding the lesion or the cortex of the contralateral side. CONCLUSION: The results emphasize the need for selection of appropriate programs tailored to the area of cortical damage in order to enhance motor functional recovery in this model.     

Association between the fMRI manifestations of activated brain areas and muscle strength in patients with space-occupying lesions in motor cortex

INTRODUCTIONThe functional magnetic resonance imaging (fMRI) study of centralnervous system (CNS) tumor around motor area has disclosed thechanges of motor function in the motor cortexes of ipsilateral andcontralateral hemispheres. This study was to obser…     

Pharmacological and PET studies in patient’s with Parkinson’s disease and a short duration-motor response: implications in the pathophysiology of motor complications

Summary. Patients with Parkinsons disease (PD) and levodopa-induced motor complications experience a short-duration response (SDR) to levodopa which can be considered the basis of motor fluctuations. The SDR is characterized by reduced response duration, increased magnitude of the response and reduced latency to the peak effect. A short latency and a high magnitude are the most salient pharmacological features of the SDR. Its pathophysiology is not totally understood. The pharmacological characteristics of the motor response to apomorphine and their relationship with 6-[¹⁸F]fluoro-L-dopa (FDOPA) and [¹¹C]raclopride (RACLO) uptake were studied in 9 patients with PD. Latency to peak effect was positively correlated with putaminal FDOPA uptake (p<0.05) and negatively correlated with RACLO uptake (P<0.05). A trend towards significance (p:0.06) between magnitude of the response and FDOPA uptake was found which were negatively correlated. Levodopa-induced dyskinesias were negatively correlated with FDOPA uptake (p<0.05) and a trend towards significance (positive correlation) with RACLO uptake was observed (p:0.07). These results suggest that both pre and postsynaptic mechanisms are involved in the origin of the SDR.     

Wernicke’s encephalopathy in a patient with acute pancreatitis: unusual cortical involvement and marvelous prognosis

Wernicke's encephalopathy (WE) is a severe neurological disorder caused by thiamine deficiency. Clinically, it is most frequently observed in people with alcohol abuse. WE, however, can occur in any clinical condition associated with malnutrition or thiamine deficiency. We present the case of a 47-year-old woman with prolonged therapeutic fasting who presented with ophthalmoplegia, ataxia and deep coma. MRI showed unusual symmetric cortical abnormalities in the frontal and parietal lobes, as well as typical lesions surrounding the third ventricle and aqueduct. Although the patient entered a vegetative state, she finally regained consciousness after thiamine supplementation unexpectedly. To the best of our knowledge, it has never been reported to date that the patient with WE in a vegetative state with cortical damage shows a marvelous prognosis, which prompts us to report this case. In the present report, we highlight the role of MRI in the diagnosis of acute WE.     

Relative paucity of tau accumulation in the small areas with abundant Aβ42-positive capillary amyloid angiopathy within a given cortical region in the brain of patients with Alzheimer pathology

Cerebral amyloid angiopathy (CAA) is a manifestation of amyloid β-protein (Aβ) accumulation in the elderly as well as in patients with Alzheimer’s disease (AD). Two types of CAA have been noted, based on the type of vasculature in which Aβ is deposited: cerebral capillary amyloid angiopathy (capCAA) and non-capCAA. Non-capCAA is a common form of CAA that consists of Aβ deposited in arteries and arterioles. Recent information on Aβ metabolism in the brain suggests that non-capCAA is associated with Aβ secretion into the cerebrospinal fluid via the perivascular space, whereas capCAA is associated with Aβ removal to blood plasma via the capillary endothelium. Aβ40, a major and relatively soluble Aβ isoform, is deposited predominantly in non-capCAA, and Aβ42, which is insoluble and associated more closely than Aβ40 with AD, is deposited predominantly in capCAA. Studying small areas of microscopic size within a given cortical region, we found an inverse association of capCAA and senile plaques. We also found a relative paucity of tau pathology in the small areas with abundant capCAA compared with the small areas with abundant senile plaques within a cortical region with the same cytoarchitecture. We suppose that both capCAA and senile plaques indicate high Aβ42 in the neuropil but that only Aβ42 in the form of insoluble deposits in senile plaques promotes tau abnormality.     

Lobular panniculitis and lipoatrophy of the thighs with interferon-ß1a for intramuscular injection in a patient with multiple sclerosis

Multiple sclerosis (MS) patients may experience severe local inflammatory skin reactions during disease-modifying therapy with subcutaneously injected interferon-β (IFN-β). It is common clinical practice to switch those patients to an intramuscularly administered formulation, where severe local skin reactions have not been described. Here we report a 42-year-old woman with stable relapsing–remitting MS, who was switched from subcutaneously to intramuscularly injected IFN-β1a due to abdominal skin necroses and slight multifocal lipoatrophy. After two years of complication-free therapy with intramuscular IFN-β1a, the patient slowly developed painful lobular panniculitis and severe lipoatrophy of both lateral thighs. A careful diagnostic workup identified misguided subcutaneous injections due to a wrong injection angle as the most plausible cause. Upon correction of her injection technique, pain and skin reddening resolved, while her disfiguring lipoatrophy was irreversible. This report should enhance awareness that severe skin adverse effects may also occur, although rarely, with IFN-β for intramuscular injection. Early recognition and correction of the injection technique may help to prevent severe complications.     

Post-stroke reorganization of brain motor output to the hand: a 2–4 month follow-up with focal magnetic transcranial stimulation

Focal transcranial magnetic stimulation (TCS) was employed for the representation of the motor cortex in a population of 18 patients to investigate the functional properties of hand motor areas 2–4 months after a monohemispheric stroke. Eleven sites were stimulated to elicit motor evoked potentials (MEPs) in abductor digiti minimi muscle after TCS of affected (AH) and unaffected (UH) hemispheres; recording sessions were performed at the beginning (T1) and after 8–10 weeks (T2) of neurorehabilitation. Barthel index and Canadian neurological scale scores were evaluated. A group of 20 healthy control subjects was enrolled. In stroke patients the AH was less excitable than normal, combined with a decrease in motor cortical output area (P<0.05) in T1. In T2, there was an enlargement of the hand motor area on the AH combined with an improvement of clinical scores (P<0.001). In T1 and T2, the amplitude of MEPs in the AH was reduced (P<0.001) with a prolongation of central conduction time (P<0.001) and with a tendency towards improvement in T2; the amplitude of contracted MEPs was larger than normal in the UH in T1. Both in T1 and T2, anomalous `hot spot' (most excitable) scalp sites, never seen in normals, were often encountered (T2>T1) on the AH and UH. Interhemispheric differences for topography and latency of MEPs were remarkably affected. Our data are consistent with a rearrangement of the brain motor cortical output between 2 and 4 months following stroke. The amelioration of the neurophysiological parameters was correlated with clinical improvement in disability and neurological scores. This study confirms the existence in adults of brain `plasticity' still operating between 2 and 4 months from an acute vascular monohemispheric insult.     

Gross motor ability in Rett syndrome – the power of expectation,motivation and planning

A main task for the physiotherapist at the Swedish Rett Center is to document and report successful treatment. This report shows the possibility to regain function, get variation and avoid contractures for several years. A thorough neurologic, orthopaedic and physiotherapeutic assessment and analysis is essential. We stress the importance of keeping the feet in good position, using surgery and well fitting orthoses when needed, making standing possible and for some persons, walking. For the effect of treatment the following factors were of vital importance: the expectations of the persons treating the girl/woman – what they believed she could do, the motivation of the girl/woman herself, a joint plan for intervention including everyone involved, and well educated personnel, well informed about Rett syndrome – its problems and possibilities.     

Effect of cued training on motor evoked potential and cortical silent period in people with Parkinson’s disease

ObjectiveTo examine whether training under visual cues could enhance motor cortical excitability and intracortical inhibition in individuals with Parkinson’s disease (PD).MethodsThis was a single blinded cross-over study. Eight individuals with PD received two sessions of 30-min pinch-grip training with and without visual cues. The visual cue was given in form of an arrow that indicated the pre-set force level on a computer screen. Outcome measures consisted of peak motor evoked potential (MEP) and cortical silent period (CSP) of the first dorsal interosseus as well as behavioural tests including Purdue pegboard test, tapping speed in 30 s, and the maximum pinch grip force exerted by the thumb and index finger.ResultsAfter cued training, there were significant increases in the peak MEP, CSP duration and tapping speed (all p < 0.05). In contrast, there was no change in all outcome measures after training under the non-cued condition.ConclusionsThirty minutes of pinch-grip training with visual cues could enhance motor cortical excitability and intracortical inhibition in individuals with PD.SignificanceThe findings on the neurophysiological changes after cued-training may inform further clinical application of visual cues to maximize motor improvement and corticomotor plasticity in people with PD.     

Reduction of β-amyloid deposits by γ-secretase inhibitor is associated with the attenuation of secondary damage in the ipsilateral thalamus and sensory functional improvement after focal cortical infarction in hypertensive rats

Abnormal β-amyloid (Aβ) deposits in the thalamus have been reported after cerebral cortical infarction. In this study, we investigated the association of Aβ deposits, with the secondary thalamic damage after focal cortical infarction in rats. Thirty-six stroke-prone renovascular hypertensive rats were subjected to distal middle cerebral artery occlusion (MCAO) and then randomly divided into MCAO, vehicle, and N-[N-(3,5-difluorophenacetyl)--alanyl]-S-phenylglycine t-butyl ester (DAPT) groups and 12 sham-operated rats as control. The DAPT was administered orally at 72 hours after MCAO. Seven days after MCAO, sensory function, neuron loss, and glial activation and proliferation were evaluated using adhesive removal test, Nissl staining, and immunostaining, respectively. Thalamic Aβ accumulation was evaluated using immunostaining and enzyme-linked immunosorbent assay (ELISA). Compared with vehicle group, the ipsilateral thalamic Aβ, neuronal loss, glial activation and proliferation, and the mean time to remove the stimulus from right forepaw significantly decreased in DAPT group. The mean time to remove the stimulus from the right forepaw and thalamic Aβ burden were both negatively correlated with the number of thalamic neurons. These findings suggest that Aβ deposits are associated with the secondary thalamic damage. Reduction of thalamic Aβ by γ-secretase inhibitor may attenuate the secondary damage and improve sensory function after cerebral cortical infarction.     

An A8296G mutation in the MT-TK gene of a patient with epilepsy - a disease-causing mutation or rare polymorphism?

Mitochondrial DNA (mtDNA) mutations are an important cause of human diseases. mtDNA could be considered a candidate modifying factor in neurodegenerative disorders. A homoplasmic A8296G mutation was detected in a 24-year-old patient with idiopathic generalized epilepsy. The A8296G mutation in the mitochondrial DNA MT-TK gene has been associated with severe mitochondrial diseases. The pathogenicity of this mutation or its association with a specific disease is unclear. This mutation has already been reported exclusively as well as together with other mutations during trials of mtDNA. As in this case, the mutation was homoplasmic and there were no clinical findings in other family members. We suggest that this mutation is a rare polymorphism or may be a pathogenic mutation in combination with other mutations outside of the MT-TK gene.     

Multifocal motor neuropathy with conduction blocks and prurigo nodularis. A paraneoplastic syndrome in a patient with non-Hodgkin B-cell lymphoma?

Multifocal motor neuropathy with conduction blocks (MMNCB) is a peripheral demyelinating neuropathy. The etiology of this disease is unknown, but an autoimmune origin is postulated. Prurigo nodularis (PN), a chronic dermatosis also having an unknown etiology and many peripheral neuropathies of different nature are associated to hematological tumors. We have found no cases in the literature in which MMNCB was presented as a paraneoplastic syndrome of a non-Hodgkin B-cell type lymphoma (NHL-B). We present the case of a 67 year old man who simultaneously developed PN and MMNCB in upper limbs and who was diagnosed of a NHL-B 19 months later. We raise the hypothesis that both prurigo and neuropathy are a paraneoplastic syndrome for lymphoma with a possible common autoimmune pathogenic mechanism.